I got the OS map app on my phone. It's £23 a year, but worth every penny, coz it's got every single OS map of the country, so wherever I am I can roam. Love it!
Noice! I tend to take a picture of the section of map before I start out. Some of the landowners round here are trying hard to pretend there is no public right of way...so I like to find those paths and have a good old tramp